I cannot modify the 'FaceAlpha' property of my 'Rectangle' object

When I create a rectangle using:

>> a=annotation('rectangle')

I can modify its 'FaceAlpha' property. However, when I create it using:

>> b=rectangle();

then there is no 'FaceAlpha' value for me to modify even though both "a" and "b" are shown as 'Rectangle' objects.

Answer 1

[MathWorks Support Team]

While both "a" and "b" are shown as 'Rectangle' objects in the Workspace, they actually come from two different classes, and therefore have different properties:

>> a = annotation('rectangle');
>> b = rectangle;

>> class(a)
ans =
    'matlab.graphics.shape.Rectangle'

>> class(b)
ans =
    'matlab.graphics.primitive.Rectangle'